Connections Between Solids and Discrete Molecules

The crystalline structure of the high-temperature superconductor YBa2Cu307, showing the different planes of copper oxide layers. Systematic oxide vacancies along the z-axis occur in the Y planes of the material. (Color legend  

TABLE 11.9 A comparison between terms used in the band theory of solids and those in MOT of discrete molecules. 

Which of the following is the best choice for a unit cell Explain your answer. 

In Example I I -2, it was proved that the packing efficiency for the fece-centered cubic Bravais lattice is 74%. What is the packing efficiency of the body-centered cubic Bra-vais lattice Show all work. 

Some elements show polymorphism they can exist in more than one type of crystalline form. Iron is an example. At room temperature, iron exists as ferrite, or a-Fe, and is a magnetic body-centered cube. Between 906-1403 °C, however, an allotrope of iron (called y-Fe) exists in a nonmagnetic fece-centered cube. 

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